Passive fire protection is used to protect objects against fire and are intended to contain fire and/or retard spreading of the fire. In general, such objects include electric cables, pipes and tanks conducting or containing hydrocarbons or other flammable materials, ventilation ducts, safety deposit boxes, penetration seals for cables and pipes in walls etc.
Heat sources include hydrocarbon fire, jet fire, hot gases, infrared radiated heat etc. Passive fire protection may use structural components such as fire-resistant walls, floors, and doors, or be in the form of e.g. an insulating layer of mineral fibres which will delay the heat from the fire in reaching the protected object on the “cold” side of the insulating layer. Other known technologies use intumescent materials which upon heating will expand and increase in volume. Still other technologies use materials which upon heating will go through one or more phases in which the material will react chemically and/or physically with one or more endothermic reactions, e.g. where hydrates are spent and water vapour is released, which has a cooling effect. Materials with such endothermic properties include polymer-based materials and rubber-based materials which are applied to the surface of the object to be protected.